Method of producing a segmented cage for roller or needle bearings



May: 17, 1966 A. PITNER 3,251,118

METHOD OF PRODUCING A SEGMENTED CAGE FOR ROLLER OR NEEDLE BEARINGSOriginal Filed June 4, 1962 2 Sheets-Sheet 1 t 1 e a, e 11 h 5 w w R w Eh L S L 0 2 R R O F E G A D N m m N A NEE Tw I E m m A G N May 17, 1966METHOD OF PRODUCIN Original Filed June 4, 1962 United States Patent3,251,118 METHOD OF PRODUCING A SEGMENTED CAGE FOR ROLLER 0R NEEDLEBEARINGS Alfred Pitner, Paris, France, assignor of one-half to NadellaS.A., Rueil-Malmaison, France, a French body corporate Originalapplication June 4, 1962, Ser. No. 199,866. Divided and this applicationMay 25, 1965, Ser. No. 458,582 Claims priority, application France, July31, 1961, 869 542 5 Claims. (31. 29-1484) This is a divisionalapplication of my application, Serial No. 199,866, filed June 4, 1962.Now Patent No. 3,199,- 935, granted-August 10, 1965.

The present invention relates to a method of producing cages in segmentsfor roller or needle bearings, for example for mounting such cages onflanged support faces or in housings having such shape that it would bediflicult or impossible to mount a cage in one piece.

It has already been proposed to provide roller or needle bearing cagesin one piece with retaining means retaining the rollers or needles inthe inward direction formed for example on the bars separating theapertures receiving the rollers or needles but these retaining meanshave been constructed in such manner that they serve to prevent the lossof the rollers or needles only during handling and no contact occurs inservice between these means and the rollers or needles; this has beenachieved by giving I effect of centrifugal force and rub heavily againstthe outer race or the extensions thereof. This results in wear,overheating, noises and even a danger of destruction of the cage.

It has been discovered that this drawback can be avoided in utilizingthe rollers or needles as support points to prevent the segments of thecage from coming in contact with the outer race under the effect ofcentrifugal force by means of elements which also act during handling asretaining means retaining the needles in the inward direction, and thatthe disadvantage of this support when the bearing is in service can beeliminated or greatly diminished by reducing the mass of the cagesubjected to centrifugal force mw R, or by reducing the pressure ofcontact by an extension of the surface or contactor by employing thesetwo types of means when the angular speed to or the mean Radius R of thecage are great enough to necessitate such precautions.

The object of the invention is therefore to provide a method ofproducing a massive segmented cage for a cylindrical roller or needlebearing and comprising apertures separated by bars whose ends areinterconnected by circumferential end rims, the flanks of said barsextending inwardly from the geometric pitch cylinder defined by the axesof the rollers or needles and converging in such manner as to offer aminimum circumferential distance therebetween which is less than thediameter of the rollers of needles, said cage being so arranged that thebars and rims of each segment constitute a single piece formed by sheetmaterial which is cut out and bent, the flanks of the bars having aplane part extending at least in the region of said pitch cylinder,and'the distance between the convergence of said'flanks and the diameterof the rollers and needles being such that the latter always projectfrom the outer cylindrical surface of each cage segment when they abutthe inner parts of said flanks.

The reduction in the mass of the segments subjected to centrifugal forcecan be achieve-d by the choice of the density of the material of whichthey are composed.

The increase in the surface of contact of the rollers of needles withthe retaining means retaining them in the inward direction can beachieved by providing a linear contact rather than a point contact whichextends along the entire length, or a large part of the length, of thegeneratrices of the rollers of needles.

Further features and advantages of the invention will be apparent fromthe ensuing description, with reference to the accompanying drawings towhich the invention is in no way limited. In the drawings:

FIG. 1 is a partial cross-sectional view of one embodiof a modificationof the cage shown in FIG. 2 and ineluding outer retaining means for theneedles;

FIG. 8 is a partial longitudinal section view of a cage segment blankshowing how the flanks of the apertures can be formed in accordance withthe embodiment shown in FIG. 7, and

FIG. 9 is a view'similar to FIG. 8 after the flanks have been formed.

With reference to FIG. 1, the reference character 1 designates a cagesegment provided with apertures 2 separated by bars 3 which areinterconnected by end strips or rims 4 and 5 (FIG. 3 and 4). A rollingelementin the form of a roller or needle 6 is located ineach aperture.

In the embodiment shown in FIG. 3, the complete cage has two segmentsbut it could be divided into a larger number of segments. Aftermounting, the ring of rollers or needles is interposed between an' outerrace 7 'of an outer bearing member and an inner race 8 of an innerbearing member.

According to the invention, the flanks of the apertures are so shapedand dimensioned relative to the diameter of the needles, that the radialdisplacement of the segments under the effect of centrifugal force islimited by the bearing of the cage segment against the rollers orneedles before the outer surface 9 of the segment comes in contact withthe outer race 7 or extensions thereon.

In the embodiment shown in FIG. 1, the flanks 10 of the apertures arerectilinear but convergent toward the axis C in the neighborhood of theaxis of the bearing, so that the inner Width d of the aperture issmaller than the diameter 2r of the roller or needle. Under theseconditions, when the cage segment 1 is urged outwardly by centrifugalforce its convergent flanks assume the position 10' tangentially of theroller or needle 6 and the outer surface 9 of the segment assumes theposition 9' and is held a suitable distance away from the race 7. Tothis end, the clearance 2AA between the flanks of the aperture and thetangents to the rolling elements 6, which are parallel with these flanksin the mean position of the cage segment, must be less than a certainvalue which is easily calculated. In this calculation it is assumed,although this is only an approximation, that the point C coincides withthe axis of the bearing. In ex- .9 tending the flanks of said tangentsup to a radius intersecting the centre C and the centre of the rollingelement, these extensions intersect said radius at BB. If a is the angleof inclination or the semi-angle of convergence of the flanks it isclear that the semi-clearance AA=BB=BC sin a. BC represents the maximumradial displacement of the cage segment, which must be less than thedifference R-R', R being the radius of curvature of the race 7 and R theradius of curvature of the outer surface 9 of the cage segment. If irepresents the clearance 2AA is is clear that the relation j 2(R-R) sina must be satisfied.

In the embodiment shown in FIG. 2, the flanks 10 of the apertures 11,which could comprise rectilinear parts, converge approximately towardthe axis of the bearing, have a curved surface 12, 12 having a radius ofcurvature r in the neighborhood of the radius of curvature of therolling element, and form with the inner surface 13 of the segment anose or shoulder D which is preferably slightly rounded. When thesegment is urged outwardly by centrifugal force its noses D or itscurved flanks 12 bear against the rolling element 6, the aperturesassuming the position 11' and the outer surface 9 of the segment theposition 9 at a suitable distance from the race 7. For this purpose, itis necessary that the clearance 2D D between the periphery of therollers or needles and the points of the noses D nearest to thisperiphery be less than a certain value which is also easily calculated.At the moment of contact, the nose D occupies the position D and DDrepresents the maximum radial displacement e of the segment. If b is theangle made b the radius OD with the radius 00 intersecting the axis ofthe hearing, it is easy to calculate that the semi-clearance DD=e cos b(neglecting the very slight dilference in the angle b for the points Dand D) and that DID! j e=--=- cos b 2 cos b must be less than R-R,whence the relation:

2(RR) cos b Depending on the values of the radii R and R and the valuesof the angles a and b, a choice is made between the solution shown inFIG. 1 and that shown in FIG. 2, bearing in mind the manufacturingtolerances determining the smallest possible clearance j and the risk ofthe rolling elements wedging (for example if the angle a is too small).

It will be observed that the convergence of the flanks shown in FIG. 1or noses such as D shown in FIG. 2, also serve to retain the rollers orneedles in the inward direction, for example during the handling of thecage independently of the races.

It will be observed that, in service, contact occurs at A (FIG. 1) orthe D (FIG. 2) between the flanks of the apertures and the rollingelements. In single-piece cages this contact is arranged if possible onthe pitch circle of the rolling elements. In a segmented cage, in orderto avoid deterioration of the segments against the race 7, this providedcontact must be arranged outside this pitch circle, but the resultingdisadvantages are eliminated or rendered practically harmless byreducing the mass of the segments in selecting a material of but littledensity (for example a plastic) or by reducing the thickness of thesegment, which need not exceed the semi-diameter 2r of the rollingelements and this might require providing no retaining means forretaining the rolling elements in the outward direction.

Further, it is well to reduce the pressure of contact at the point A orD by an extension of the surface of contact. A linear contactover theentire length of the generatrices of the rolling elements intersecting Aor D, or

in any case over a large part of said length (rather than a pointcontact at one of several points), usually provides a solution to thisdifficulty but it is also possible to obtain a surface contact by givingthe surface 12 the same radius as the rolling element, either by aprecise calibration or by the running-in achieved automatically inservice.

The small thickness of the cage makes available a large space for anabundant reserve of lubricant.

To preclude scratching of the rolling elements by the noses such as D inthe embodiment shown in FIG. 2, these noses are slightly radiused orrounded, as already mentioned.

A cage segment such as that described can be produced by variousmethods, but it is convenient to obtain it by blanking out from stripmaterial and bending.

As shown in FIG. 4, the starting material or stock can be in the form ofa flat strip or band in which the apertures 2 are pierced. The bendingof this blank automatically provides the convergence of the flanks, asshown in FIG. 1.

To shape the flanks provided with noses or bearing shoulders as shown inFIG. 2, a stamping or swaging operation could be used. FIGS. 5 and 6show an example of such an operation.

The blank shown in FIG. 4 is punched on a die E (FIG. 5) by means ofpunches F. The solid parts of the die are provided with rounded corners13 so that the punches form in the blank lips 16 which slightly projecttherefrom. In a second stage, the blank is placed on a flat anvil I andpunches H having rounded edges straighten the lips against the anvil soas to form the noses D, the small radius being obtained in providing asuitable shape to the edges of the punch.

If the apertures of the segments are desired to be provided withretaining means retaining the rolling elements 6 in the outwarddirection, the flank shape shown in FIG. 7 could be adopted, theseflanks comprising on the outer side of the cage segment projections ornoses 14 which reduce the width of the aperture to a value less than thediameter of the element 6. These noses 14 can be connected torectilinear convergent flanks 11, and if desired, the latter couldinclude curved parts 12 with noses D.

To form the noses 14 a punching and forming operation as illustrated inFIGS. 5 and 6 is performed but the blank is bent in a direction oppositeto that previously described. Thus, as the noses 14 are located in FIG.5 in the same position as the noses D, the blank i bent in such mannerthat the noses 14 are located on the convex surface of the segment.

If it is desired to provide both the noses ,14 and the noses D, it ispossible to proceed as illustrated in FIGS. 8 and 9, where H representsthe forming punches producing the noses D (FIG. 9) and I represents aforming punch producing the noses 14, the noses D and 14 being of coursein staggered relation along the length of the aperture so as to permitoperation of these punches.

In the course of production of the segment, lubricant passages could beformed in certain regions and in particular toward the middle of thebars 3, since it is above all toward the parts located near the ends ofthe rolling elements that the retaining action of the segment is mosteffective. Indeed, in actual operation the contact between the rollingelements and the faces of the bars is more frequent and intimate atthese parts and this insures the guiding of the rolling elements.

Limitation of an out-of-centre condition of the cage segments must beachieved as mentioned hereinbefore by the bearing of a portion of eachsegment located substantially on the same generatrix, so as to easilyafford a precise and cheap construction of each bar and insure thecontact between this generatrix and a portion of the bar constituted bya plane or curved surface coinciding with the plane tangent to theconsidered generatrix or but little removed from-this plane.

The invention applies essentially to cage segments for rolling elementsconstituted by needles or rollers having a small diameter relative totheir length, but it could be employed for other forms of rollingelements, for example elements having a slightly convex generatrix.

It must be understood that the cage elements according to the inventioncould be so constructed as to receive a plurality of rows of rollingelements.

Although specific embodiments of the invention have been described, manymodifications and changes may be made therein without departing from thescope of the invention as defined in the appended claims.

In the course of production of the segment, lubricant passages could beformed in certain regions and in par ticular toward the middle of thebars 3, since it is above all toward the parts located near the ends ofthe rolling elements that the retaining action of the segment is mosteifective. Indeed, in actual operation the contact between the rollingelements and the faces of the bars is more frequent and intimate atthese parts and this insures the guiding of the rolling elements.

Limitation of an out-of-center condition of the cage segments must beachieved as mentioned hereinbefore by the bearing of a portion of eachsegment located substantially on the same generatrix, so as to easilyafford a precise and cheap construction of each bar and insure thecontact between this generatrix and a portion of the bar constituted bya plane or curved surface coinciding with the plane .tangent to theconsidered generatrix or but little removed from this plane.

The invention applies essentially to cage segments for rolling elementsconstituted by needles or rollers having a small diameter relative totheir length, but it could be employed for other forms of rollingelements, for example elements having a slightly convex generatrix.

It must be understood that the cage elements according to the inventioncould be so constructed as to receive a plurality of rows of rollingelements.

Although specific examples of the method according to the invention havebeen described, many modifications and changes may be made thereinwithout departing from the scope of the invention as defined in theappended claims.

What I claim and desire to secure by Letters Patent is:

1. Method of producing a part-cylindrical segment of a cage for therolling elements of a bearing, consisting of the steps of taking a stripof material having a length which is such that the subsequently producedpart-cylindrical segment subtends an angle of no more than 180 at thecenter of curvature of the segment, piercing a row of spaced aperturesin the strip of material so as to form between the apertures barshaving'a rectangular cross-sectional shape in a plane containing saidrow of apertures, said row extending longitudinally of the strip and thebars extending transversely of the strip and bending the strip so thatit assumes the shape of a portion of a cylinder having an axis parallelto said bars, whereby the adjacent flanks of bars defining the sameaperture taper inwardly of said cylinder, the width between adjacentflanks defining the same aperture, measured longitudinally of said stripon the concave side of the strip, being less than the width of therolling elements to such extent that when the rolling elements radiallyabut said flanks they protrude from the outer convex side of the strip.

2. Method of producing a segment of a cage for the rolling elements of abearing, comprising the steps of piercing by means of first punches anda die a row of spaced apertures in a strip of material thereby formingbars between the apertures, said row extending longitudinally of thestrip and the bars extending transversely of the strip; the die havingpunch-receiving openings which have rounded edges extending transverselyof said row, whereby the punches deform portions of the bars adjacentsaid rounded edges when piercing the apertures and produce on the flanksof the bars depending lips extending transversely of 'said row; placingthe pierced strip on an anvil with said lips bearing on the anvil;pressing second punches between the bars against the anvil, the secondpunches having rounded edges extending transversely of said row, wherebythe second punches substantially flatten the face of the strip adjoiningthe anvil and urge the lips inwardly of the apertures and thereby forminwardly extending nose portions on said flanks; and bending the stripso that it assumes substantially the shape of a portion of a cylinderhaving an axis parallel to the bars with the nose portions on the Wardlyof said cylinder, the width bet-ween adjacent flanks of bars definingthe same aperture are made to taper inwardly o fsaid cylinder, the widthbetween adjacent flanks defining the same aperture, measured betweensaid nose portions, being less than the diameter of said rollingelements to such extent that when the rolling elements radially a-butsaid nose portions the elements protrude from the outer convex face ofthe strip.

3. Method of. producing a segment of a cage for the rolling elements ofa bearing, comprising the. steps of piercing by means of first punchesand a die a row of spaced apertures in a strip of material therebyforming bars between the apertures, said row extending longitudinally ofthe strip and the bars extending transversely of the strip; the diehaving punch-receiving openings which have rounded edges extendingtransversely of said 7 row, whereby the punches deform portions of thebars adjacent said rounded edges when piercing the apertures and produceon the flanks of the bars depending lips extending transversely of saidrow; placing the pierced strip on an anvil with said lips bearing on theanvil; pressing second punches between adjacent bars against the anvil,the second punches having rounded edges extending transversely of saidrow, whereby the second punches substantially flatten the face of thestrip adjoining the anvil and urge the lips inwardly of the aperturesand there-by form inwardly extending nose portions on said flanks; andbending the strip so that it assumes the shape of a portion of acylinder having an axis parallel to the bars with the nose portions onthe convex side of the strip, whereby the flanks of adjacent barsdefining the apertures are made to taper inwardly of said cylinder, thewidth between adjacent flanks defining the same aperture measuredbetween the nose portions being less than the diameter of said rollingelements whereby the latter are retained in the strip in the outerradial direction and the Width between adjacentflanks defining the sameaperture measured on the concave faceof the strip, being less than thediameter of said rolling elements to such extent that when the rollingelements radially abut said nose portions the elements protrude from theouter convex face of the strip.

4. Method of producing a segment of a cage for the rolling elements of abearing, comprising the steps of piercing by means of first punches anda die a row of spaced apertures in a strip of material thereby formingbars between the apertures, said row extending longitudinally of thestrip'and the bars extending transversely of the strip; the die havingpunch-receiving openings which have rounded edges extending transverselyof said row, whereby the punches deform portions of the bars adjacentsaid rounded edges when piercing the apertures and produce on the flanksof the bars depending lips extending transversely of said row; placingthe pierced strip on an anvil with said lips bearing on the anvil;pressing second punches between the bars against the anvil, the secondpunches having rounded edges extending transversely of said row, wherebythe second punches substantially flatten the face of the bars adjoiningthe anvil and urge the lips inwardly ofthe apertures and thereby forminwardly extending nose portions on said flanks; and bending the stripso that it assumes the shape of a portion of a cylinder having an axisparallel to the bars, whereby the adjacent flanks of bars defining thesame aperture are made to taper inwardly of said cylinder, the widthbetween said nose portions of adjacent flanks defining the sameaperture, being less than the diameter of said rolling elements to suchextent that when the rolling elements radially abut said nose portionsthe elements protrude from the strip.

5. Method of producing a segment of a cage for the rolling elements of abearing, comprising piercing a row of spaced apertures in a strip ofmaterial thereby forming bars between the apertures, said row extendinglongitudinally of the strip and the bars extending transversely of thestrip, each aperture being partially pierced by first punchescooperating with punch-receiving openings in a first die, and partiallypierced by a second punch which is intermediate the first punches andpierces in a direction opposed to the piercing direction of the firstpunches and cooperates with a punch-receiving opening in a second die,said punch-receiving openings having rounded edges extendingtransversely of said row, whereby the first punches and second punchesdeform portions of the bars adjacent said rounded edges when piercingthe apertures and respectively produce on the flanks of the barsdownwardly and upwardly projecting lips extending transversely of saidrow, placing the pierced strip against flat anvil means with the lipsbearing against the anvil. means, pressing third and fourth punchesbetween the bars and against the anvil means so as to flatten both facesof the strip and urge the lips respectively produced by the first andsecond punches inwardly of the apertures and thereby form inwardlyextending nose portions on said flanks, and bending the strip so that itassumes substantially the shape of a portion of a cylinder having anaxis parallel to the bars, the width between adjacent flanks definingthe same aperture, measured between the nose portions on the convex faceof the strip, being less than the diameter of said rolling elements, andthe width between adjacent flanks defining the same aperture, measuredbetween the nose portions on the concave face of the strip, being lessthan the diameter of said rolling elements to such extent that when therolling elements radially abut said nose portions the elements protrudefrom the outer convex face of the strip, the rolling elements also beingretained by the nose portions on the convex face of the strip radiallyand outwardly of the strip.

References Cited by the Examiner UNITED STATES PATENTS 1,928,823 10/1933Young 308-217 2,288,564 6/1942 Gales 29-l48.4 3,199,935 8/1965 Pitner308-217 JOHN F. CAMPBELL, Primary Examiner.

THOMAS H. EAGER, Examiner.

1. METHOD OF PRODUCING A PART-CYLINDRICAL SEGMENT OF A CAGE FOR THEROLLING ELEMENTS OF A BEARING, CONSISTING OF THE STEPS OF TAKING A STRIPOF MATERIAL HAVING A LENGTH WHICH IS SUCH THAT THE SUBSEQUENTILYPRODUCED PART-CYLINDRICAL SEGMENT SUBTENDS AN ANGLE OF NO MORE THAN 180*AT THE CENTER OF CURVATURE OF THE SEGMENT, PIERCING A ROW OF SPACEDAPERTURES IN THE STRIP OF MATERIAL SO AS TO FORM BETWEEN THE APERTURESBARS HAVING A RECTANGULAR CROSS-SECTIONAL SHAPE IN A PLANE CONTAININGSAID ROW OF APERTURES, SAID ROW EXTENDING LONGITUDINALLY OF THE STRIPAND THE BARES EXTENDING LONGITUDINALLY OF THE STRIP AND BENDING THESTRIP SO THAT IT ASSUMES THE SHAPE OF A PORTION OF A CYLINDER HAVING ANAXIS PARALLEL TO SAID BARS, WHEREBY THE ADJACENT FLANKS OF BARS DEFININGTHE SAME APERTURE TAPER INWARDLY OF SAID CYLINDER, THE WIDTH BETWEENADJACENT FLANKS DEFINING THE SAME APERTURE, MEASURED LONGITUDINALLY OFSAID STRIP ON HE CONCAVE SIDE OF THE STRIP, BEING LESS THAN THE WIDTH OFTHE ROLLING ELEMENTS TO SUCH EXTENT THAT WHEN THE ROLLING ELEMENTSRADIALLY ABUT SAID FLANKS THEY PROTRUDE FROM THE OUTER CONVEX SIDE OFTHE STRIP.